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  28  <H3><A NAME="8_1_4">8.1.4 Adding a second Y-scale</A></H3>
  29  <P> As you saw in the preceding example you could add multiple plots to
  30   the same graph and Y-axis. However what if the two plots you want to
  31   display in the graph has very different ranges. One might for example
  32   have Y-values like above but the other might have Y-values in the
  33   100:s. Even though it is perfectly possible to add them as above the
  34   graph with the smallest values will have a very low dynamic range since
  35   the scale must accomplish the bigger dynamic range of the second plot.</P>
  36  <P> The solution to this is to use a second Y-axis with a different
  37   scale and add the second plot to this Y-axis instead. Let's take a look
  38   at how that is accomplished.</P>
  39  <P> First we need to create a new data array with large values and
  40   secondly we need to specify a scale for the Y2 axis. This is done by
  41   the lines<DIV class="phpscript"><CODE><FONT color="#000000"> <FONT color="#0000BB">
  42  &nbsp;$y2data&nbsp;</FONT><FONT color="#007700">=&nbsp;array(</FONT><FONT color="#0000BB">
  43  354</FONT><FONT color="#007700">,</FONT><FONT color="#0000BB">200</FONT><FONT
  44  color="#007700">,</FONT><FONT color="#0000BB">265</FONT><FONT color="#007700">
  45  ,</FONT><FONT color="#0000BB">99</FONT><FONT color="#007700">,</FONT><FONT
  46  color="#0000BB">111</FONT><FONT color="#007700">,</FONT><FONT color="#0000BB">
  47  91</FONT><FONT color="#007700">,</FONT><FONT color="#0000BB">198</FONT><FONT
  48  color="#007700">,</FONT><FONT color="#0000BB">225</FONT><FONT color="#007700">
  49  ,</FONT><FONT color="#0000BB">293</FONT><FONT color="#007700">,</FONT><FONT
  50  color="#0000BB">251</FONT><FONT color="#007700">);
  51  <BR></FONT><FONT color="#0000BB">$graph</FONT><FONT color="#007700">-&gt;</FONT><FONT
  52  color="#0000BB">SetY2Scale</FONT><FONT color="#007700">(</FONT><FONT color="#DD0000">
  53  &quot;lin&quot;</FONT><FONT color="#007700">);</FONT><FONT color="#0000BB"></FONT></FONT>
  54  </CODE></DIV></P>
  55  <P> and finally we create a new line plot and add that to the second
  56   Y-axis. Note that we here use a new method, AddY2(), since we want this
  57   plot to be added to the second Y-axis. Note that JpGraph will only
  58   support two different Y-axis. This is not considered a limitation since
  59   using more than two scales in the same graph would make it very
  60   difficult to interpret the meaning of the graph.</P>
  61  <P> To make the graph a little bit more esthetic pleasing we use
  62   different colors for the different plots and let the two different
  63   Y-axis get the same colors as the plots.</P>
  64  <P> The resulting graph is shown below. source)<DIV class="example">
  65  <BR> <A href="exframes/frame_example5.html" target="blank"><IMG border="0"
  66  HEIGHT="200"  src="img/example5.png" WIDTH="300"></A>
  67  <BR><B>Figure 10:</B> Adding a second Y-scale plot to the same graph <A href="exframes/frame_example5.html"
  68  target="blank">[src]</A>&nbsp;
  69  <P></P>
  70  </DIV></P>
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